releases/2.6.38.8/igmp-call-ip_mc_clear_src-only-when-we-have-no-users-of-ip_mc_list.patch

   1 From 802d2fd9b43a5cf7cafca72683c7fb0458b6cab2 Mon Sep 17 00:00:00 2001
   2 From: Veaceslav Falico <vfalico@redhat.com>
   3 Date: Mon, 23 May 2011 23:15:05 +0000
   4 Subject: igmp: call ip_mc_clear_src() only when we have no users of ip_mc_list
   5
   6
   7 From: Veaceslav Falico <vfalico@redhat.com>
   8
   9 [ Upstream commit 24cf3af3fed5edcf90bc2a0ed181e6ce1513d2dc ]
  10
  11 In igmp_group_dropped() we call ip_mc_clear_src(), which resets the number
  12 of source filters per mulitcast. However, igmp_group_dropped() is also
  13 called on NETDEV_DOWN, NETDEV_PRE_TYPE_CHANGE and NETDEV_UNREGISTER, which
  14 means that the group might get added back on NETDEV_UP, NETDEV_REGISTER and
  15 NETDEV_POST_TYPE_CHANGE respectively, leaving us with broken source
  16 filters.
  17
  18 To fix that, we must clear the source filters only when there are no users
  19 in the ip_mc_list, i.e. in ip_mc_dec_group() and on device destroy.
  20
  21 Acked-by: David L Stevens <dlstevens@us.ibm.com>
  22 Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
  23 Signed-off-by: David S. Miller <davem@davemloft.net>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  25 ---
  26  net/ipv4/igmp.c |   10 +++++-----
  27  1 file changed, 5 insertions(+), 5 deletions(-)
  28
  29 --- a/net/ipv4/igmp.c
  30 +++ b/net/ipv4/igmp.c
  31 @@ -1172,20 +1172,18 @@ static void igmp_group_dropped(struct ip
  32
  33         if (!in_dev->dead) {
  34                 if (IGMP_V1_SEEN(in_dev))
  35 -                       goto done;
  36 +                       return;
  37                 if (IGMP_V2_SEEN(in_dev)) {
  38                         if (reporter)
  39                                 igmp_send_report(in_dev, im, IGMP_HOST_LEAVE_MESSAGE);
  40 -                       goto done;
  41 +                       return;
  42                 }
  43                 /* IGMPv3 */
  44                 igmpv3_add_delrec(in_dev, im);
  45
  46                 igmp_ifc_event(in_dev);
  47         }
  48 -done:
  49  #endif
  50 -       ip_mc_clear_src(im);
  51  }
  52
  53  static void igmp_group_added(struct ip_mc_list *im)
  54 @@ -1322,6 +1320,7 @@ void ip_mc_dec_group(struct in_device *i
  55                                 *ip = i->next_rcu;
  56                                 in_dev->mc_count--;
  57                                 igmp_group_dropped(i);
  58 +                               ip_mc_clear_src(i);
  59
  60                                 if (!in_dev->dead)
  61                                         ip_rt_multicast_event(in_dev);
  62 @@ -1431,7 +1430,8 @@ void ip_mc_destroy_dev(struct in_device
  63                 in_dev->mc_list = i->next_rcu;
  64                 in_dev->mc_count--;
  65
  66 -               igmp_group_dropped(i);
  67 +               /* We've dropped the groups in ip_mc_down already */
  68 +               ip_mc_clear_src(i);
  69                 ip_ma_put(i);
  70         }
  71  }